SPS制备亚微米晶氧化铝陶瓷

Fabrication of Sub-micron Alumina by Spark Plasma Sintering

以商业α-Al_2O_3粉体为原料,MgO为烧结助剂,采用放电等离子烧结技术(SPS)制备亚微米晶氧化铝陶瓷.系统研究了烧结温度、烧结助剂含量对亚微米晶氧化铝陶瓷的致密化过程及显微结构的影响.分析结果表明,1250℃以及0.05wt%分别是最佳的烧结温度和烧结助剂含量;在此条件下获得的亚微米晶氧化铝陶瓷,其相对密度达到99.8%TD(theoretical density),平均晶粒尺寸约0.68μm,显微硬度(HV5)达到20.75GPa,在3～5μm中红外范围内直线透过率超过83%.当MgO掺杂量超过0.1wt%时,第二相MgAl_2O_4形成,引起光散射,降低红外透过率.

Sub-micron alumina ceramics were fabricated by spark plasma sintering technique （SPS）, using commercial α-Al2O3 powders as starting material and MgO as sintering-aid. The effects of sintering temperature and sintering-aid content on densification and grain growth of sub-micron alumina were systemically studied. The results show that the optimal sub-micron alumina is obtained by sintering at 1250℃ for 5min under 60MPa, doped with 0.05wt%MgO. The relative density and the average grain size are 99.8%TD and 0.68um, respectively. Moreover, the Vickers hardness can reach 20.75GPa （HV5）, and the in-line transmission （hnm thickness） in the 3 5um mid-infrared range is measured beyond 83%. However, second phase MgAl2O4 is found in the samples doped with more than 0.1wt%MgO, resulting in a lower transmittance because of light scattering.